SQL 语法
The SQL SELECT StatementThe SELECT statement is used to select data from a table. The tabular result is stored in a result table (called the result-set).
Syntax
SELECT column_name(s)
FROM table_name
Note: SQL statements are not case sensitive. SELECT is the same as select.
SQL SELECT Example
To select the content of columns named "LastName" and "FirstName", from the database table called "Persons", use a SELECT statement like this:
SELECT LastName,FirstName FROM Persons
The database table "Persons":
LastName
FirstName
Address
City
Hansen
Ola
Timoteivn 10
Sandnes
Svendson
Tove
Borgvn 23
Sandnes
Pettersen
Kari
Storgt 20
Stavanger
The result
LastName
FirstName
Hansen
Ola
Svendson
Tove
Pettersen
Kari
Select All Columns
To select all columns from the "Persons" table, use a * symbol instead of column names, like this:
SELECT * FROM Persons
Result
LastName
FirstName
Address
City
Hansen
Ola
Timoteivn 10
Sandnes
Svendson
Tove
Borgvn 23
Sandnes
Pettersen
Kari
Storgt 20
Stavanger
The Result Set
The result from a SQL query is stored in a result-set. Most database software systems allow navigation of the result set with programming functions, like: Move-To-First-Record, Get-Record-Content, Move-To-Next-Record, etc.
Programming functions like these are not a part of this tutorial. To learn about accessing data with function calls, please visit our ADO tutorial.
Semicolon after SQL Statements?
Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server.
Some SQL tutorials end each SQL statement with a semicolon. Is this necessary? We are using MS Access and SQL Server 2000 and we do not have to put a semicolon after each SQL statement, but some database programs force you to use it.
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